The present invention relates to an image forming apparatus such as an electrophotographic apparatus or a static recording apparatus, a method for forming images using this apparatus, and a developing agent for use in this apparatus.
An electrophotographic apparatus or a static recording apparatus forms an image by using a photoreceptor or a derivative to form an electrostatic latent image on an image carrier, using a toner to develop and visualize the electrostatic latent image, transferring the obtained toner image to an image receiving member, and then fixing the image. Conventionally known fixing techniques include the heating fixing method, the pressure fixing method, the high-frequency heat fixing method, the electromagnetic induction heating method, and the combined fixing method that is a combination of the flush fixing method and the electromagnetic induction heating method.
In particular, the electromagnetic induction heating method is known as a technique capable of reducing the size of the apparatus, the warm-up time, and the amount of energy required. This technique installs an exciting coil in pressure means and carries out heating using, as a heat source, Joule heat generated by applying high-frequency magnetic fields to a magnetized metallic surface of heating means provided opposite to the pressure means.
The electromagnetic induction heating method, however, is disadvantageous in that the temperature distribution on the surface of the heating means may not be uniform. For example, a phenomenon may occur in which part of the heating means surface which corresponds to a width-wise central portion of the image receiving member is hot, while parts of the heating means surface which correspond to opposite ends thereof are cool. In this case, images of a stable image density cannot be obtained. In addition, parts of the heating means surface by which the image receiving member has passed may is cooled because the heat transfers to the material, while parts thereof by which the material has not passed become hotter than required, resulting in offsets in the end portion of the material.